In an existing IP Multimedia Subsystem (IMS) architecture of the 3GPP, most application services may be provided by an Application Server (AS). Provision of an application service for a user session by using a kind of AS is determined dependent upon an initial Filter Criteria (iFC) in a user service profile.
In the related art, a Cx interface is set between a Serving Call Session Control Function (S-CSCF) and a Home Subscriber Server (HSS).
The concept of IMS communication Service Identifier (SID) in an IMS domain, and thus defines application demands and a basic architecture for the SID. An important demand for using the SID is to identify each separate service.
In the related art, a network entity which needs to use the IMS communication service identifier cannot acquire any IMS communication service identifier and further cannot perform corresponding operations dependent upon the IMS communication service identifier.